The appearance of pancakes depends on how water escapes the batter mix during the cooking process and this varies with the thickness of the batter, according to UCL research co-authored by Professor Sir Peng Khaw, director of the National Institute of Health's Biomedical Research Centre at Moorfields Eye Hospital, and University College of London's Institute of Ophthalmology. Understanding the physics of the process offers important insights into how flexible sheets, like those found in human eyes, interact with flowing vapor and liquids.

The study, published in Mathematics Today, compared recipes for 14 different types of pancakes from across the world including the Canadian ploye and Malaysian lempeng kelapa. For each pancake style, researchers measured the aspect ratio, the pancake's diameter cubed in relation to the batter's volume, and the thickness of the batter.

Investigators found that thin batters that spread easily in the pan ended up with a smooth surface pattern and less burning as the vapor flow buffered the heat of the pan. Thick batters formed pancakes with irregular craters on the bottom surface, as water vapors were trapped during cooking, unevenly lifting the pancake from the pan.

Dr. Khaw noted, “We work on better surgical methods for treating glaucoma, which is a build-up of pressure in eyes caused by fluid. To treat this, surgeons create an escape route for the fluid by carefully cutting the flexible sheets of the sclera. We are improving this technique by working with engineers and mathematicians. It’s a wonderful example of how the science of everyday activities can help us with the medical treatments of the future.”